Touch is not working

A client brings me this S4, turns on, not cracked. but touch don't really work. Every now and then it might pick up something. So he leaves it with me. I order a new LCD assembly. He calls back said his wife dropped it in water. Ok. Took phone apart soaked in alcohol rubbed it down with a que tip. Put a heat gun to the parts for a second just to get warm and make sure everything was evaporated. Installed new Screen. Nothing, No picture. Connected Old screen to test. Phone boots up but still no touch. So i am thinking maybe the new screen is bad..... Take all the parts out of the new assembly and put back into old. Hook up new screen outside of assembly. Comes on, I have picture but no touch. Any ideas?